中文摘要：

针对无线传感器网络MAC协议的作用与要求,给出一种基于CDMA的MAC协议改进方案.根据网络负载变化采用周期性的侦听/睡眠机制,使大多数节点处于睡眠状态,节省能耗;同时结合CDMA技术给节点分配网内唯一的具有正交性的高速伪随机码（PN）来调制数据信号,使之在时域和频域重叠,实现数据的大规模实时传送.仿真结果表明,协议在保证系统低延时和高吞吐量的同时,能明显减少能量消耗.

英文摘要：

Aiming at the functions and requirements of the MAC protocols in Wireless Sensor Networks,this paper proposes an improved MAC protocol based on CDMA.According to the changes of network traffic,listen/sleep mechanism keeped most nodes in sleeping to save energy.And combined the technology of CDMA,the nodes used the high-speed pseudo-random code（PN） with the characteristics of uniqueness in network and orthogonality to modulate data signals,which can be overlapped in time and frequency,to achieve transmission in large-scale and real-time.Simulation results show that the protocol not only maintain lower system delay and higher throughput,but also reduce energy consumption obviously.